1. Field of the Invention
The present invention generally relates to a motor of a ceiling fan and, more particularly, to a motor equipped with a core arranged between a rotatable first housing and a steady second housing with the first housing capable of rotating relative to the second housing.
2. Description of the Related Art
Referring to FIG. 1, a conventional motor of a ceiling fan with a reference number of “9” of Taiwan publication number M354002 entitled “Motor of Ceiling Fan” is shown as including a stator 91, a rotor 92, and a controller 93. The stator 91 has a shaft 911, a core 912 coupled around the shaft 911, and a plurality coils 913 surrounding the core 912. The rotor 92 is rotatably coupled around the shaft 911 and has an upper shield 921, a lower shield 922 and a waist ring 923 sandwiched by the upper and lower shields 921, 922. The upper and lower shields 921, 922 are positioned on two opposite sides of the core 912. The controller 93 includes a circuit board 931 and a housing 932 receiving the circuit board 931.
Since the upper shield 921, the lower shield 922 and the waist ring 923 seal the stator 91 jointly, it is difficult to dispel the heat generated by the core 912 and coils 913 in operation from the stator 91. As a result, the stator 91 is continuously kept at a high temperature in operation, which results in negative effects to the performance and lifetime of the conventional motor 9 and also induces increased operational currents. Moreover, even though there may be some apertures in the upper shield 921, the lower shield 922 or the waist ring 923 for cooling purposes, it is not easy to generate airflows in the motor 9 for air inside and outside the rotor 92 to exchange due to the simultaneous rotation among the upper shield 921, the lower shield 922 and the waist ring 923. Consequently, the internal air of the rotor 92 cannot sufficiently exchange with the external air, and the heat generated by the core 912 and the coils 913 still remains in the motor 9 without being properly expelled via the apertures. The inadequate heat dissipation mechanism will lead to the accumulation of heat inside the motor 9, which further causes the malfunction of the motor 9, shortens the service life of the motor 9, and increases the power consumption of the motor 9.
In addition to the stator 91, electronic elements of the circuit board 931 usually also generate heat in operation. Although the circuit board 93.1 is arranged outside of the stator 91 and rotor 92 to avoid heat accumulation, the housing 932 for receiving and being connected by the circuit board 931 largely increases the size of the motor 9.
As a result, since the conventional motor 9 for a ceiling fan has drawbacks such as “bad performance in cooling” and “large size,” it is necessary to improve the conventional motor 9.